add one_color_no_palette.webp

this lossless file was produced with:
b6513fba Do not use a palette for one color images.

at 28 bytes it exercises a minimum size check failure in chrome and a one
color image related failure in safari/ios/macos.

https://chromium-review.googlesource.com/c/chromium/src/+/2876279

Bug: b/186640109,b/188702956
Change-Id: Ibb05749a4ff04228f70ae37501ee64fdf234e566
diff --git a/libwebp_tests.md5 b/libwebp_tests.md5
index 64b398b..8c55eb9 100644
--- a/libwebp_tests.md5
+++ b/libwebp_tests.md5
@@ -468,3 +468,8 @@
 1700bae9a667cd9478ba2b8a969491df  big_endian_bug_393.webp.pgm
 f8d4f927b7dc47d52265a7951b6eb891  big_endian_bug_393.webp.ppm
 ffc5abfa7d15035bafc4285faece9b9a  big_endian_bug_393.webp.tiff
+26a90ddfe0a3db7aaa5476c36bc12a5c  one_color_no_palette.webp.bmp
+072fae41cc90c68ac5a2c6ec142c8336  one_color_no_palette.webp.pam
+007a55a92c8a30aebe871a306101bc78  one_color_no_palette.webp.pgm
+7a78b4d026f256887897bed7f84de225  one_color_no_palette.webp.ppm
+02c3b670d9082c52f5bc089c669f0f85  one_color_no_palette.webp.tiff
diff --git a/one_color_no_palette.webp b/one_color_no_palette.webp
new file mode 100644
index 0000000..4410fb9
--- /dev/null
+++ b/one_color_no_palette.webp
Binary files differ